Hey guys, particularly Alexey. ( bug report case # 605471)
Texture2D.LoadImage is slow. I’ve created a method to asynchronously load textures from files on disk on iOS. This is fast as hell and runs circles around Texture2D.LoadImage. Basically, you provide an URL of the image on disk you want to load, and it’ll load the file asynchronously. I haven’t heavily tested my method that resizes the texture if you ask it to, but resize == false version I tested a bunch.
usage:
mediaTexture = FastTexture2D.CreateFastTexture2D(media.url, false, media.w, media.h, GotFastTexture);
(GotFastTexture is a delegate of Action OnFastTexture2DLoaded; )
Here’s a C# class:
using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System;
using System.IO;
using System.Runtime.InteropServices;
public class FastTexture2D : ScriptableObject {
//(c) Brian Chasalow 2014 - brian@chasalow.com
[AttributeUsage (AttributeTargets.Method)]
public sealed class MonoPInvokeCallbackAttribute : Attribute {
public MonoPInvokeCallbackAttribute (Type t) {}
}
[DllImport ("__Internal")]
private static extern void DeleteFastTexture2DAtTextureID(int id);
[DllImport ("__Internal")]
private static extern void CreateFastTexture2DFromAssetPath(string assetPath, int uuid, bool resize, int resizeW, int resizeH);
[DllImport ("__Internal")]
private static extern void RegisterFastTexture2DCallbacks(TextureLoadedCallback callback);
public static void CreateFastTexture2D(string path, int uuid, bool resize, int resizeW, int resizeH){
#if UNITY_EDITOR
#elif UNITY_IOS
CreateFastTexture2DFromAssetPath(path, uuid, resize, resizeW, resizeH);
#endif
}
public static void CleanupFastTexture2D(int texID){
#if UNITY_EDITOR
#elif UNITY_IOS
DeleteFastTexture2DAtTextureID(texID);
#endif
}
private static int tex2DCount = 0;
private static Dictionary<int, FastTexture2D> instances;
public static Dictionary<int, FastTexture2D> Instances{
get{
if(instances == null){
instances = new Dictionary<int, FastTexture2D>();
}
return instances;
}
}
[SerializeField]
public string url;
[SerializeField]
public int uuid;
[SerializeField]
public bool resize;
[SerializeField]
public int w;
[SerializeField]
public int h;
[SerializeField]
public int glTextureID;
[SerializeField]
private Texture2D nativeTexture;
public Texture2D NativeTexture{ get{ return nativeTexture; }}
[SerializeField]
public bool isLoaded = false;
public delegate void TextureLoadedCallback(int nativeTexID, int original_uuid, int w, int h);
[MonoPInvokeCallback (typeof (TextureLoadedCallback))]
public static void TextureLoaded(int nativeTexID, int original_uuid, int w, int h){
if(Instances.ContainsKey(original_uuid) nativeTexID > -1){
FastTexture2D tex = Instances[original_uuid];
tex.glTextureID = nativeTexID;
tex.nativeTexture = Texture2D.CreateExternalTexture(w, h, TextureFormat.ARGB32, false, true, (System.IntPtr)nativeTexID);
tex.nativeTexture.UpdateExternalTexture( (System.IntPtr)nativeTexID);
tex.isLoaded = true;
tex.OnFastTexture2DLoaded(tex);
}
}
private Action<FastTexture2D> OnFastTexture2DLoaded;
protected void InitFastTexture2D(string _url, int _uuid, bool _resize, int _w, int _h, Action<FastTexture2D> callback){
this.url = _url;
this.uuid = _uuid;
this.resize = _resize;
this.w = _w;
this.h = _h;
this.glTextureID = -1;
this.OnFastTexture2DLoaded = callback;
this.isLoaded = false;
}
private static bool registeredCallbacks = false;
private static void RegisterTheCallbacks(){
if(!registeredCallbacks){
registeredCallbacks = true;
#if UNITY_IOS
if(Application.platform == RuntimePlatform.IPhonePlayer)
RegisterFastTexture2DCallbacks(TextureLoaded);
#endif
}
}
//dimensions options: if resize is false, w/h are not used. if true, it will downsample to provided dimensions.
//to create a new texture, call this with the file path of the texture, resize parameters,
//and a callback to be notified when the texture is loaded.
public static FastTexture2D CreateFastTexture2D(string url,bool resize, int assetW, int assetH, Action<FastTexture2D> callback){
//register that you want a callback when it's been created.
RegisterTheCallbacks();
//the uuid is the instance count at time of creation. you pass this into the method to grab the gl texture, and it returns the gl texture with this uuid
int uuid = tex2DCount;
tex2DCount = (tex2DCount +1 ) % int.MaxValue;
FastTexture2D tex2D = ScriptableObject.CreateInstance<FastTexture2D>();
tex2D.InitFastTexture2D(url, uuid, resize, assetW, assetH, callback);
//call into the plugin to create the thing
CreateFastTexture2D(tex2D.url, tex2D.uuid, tex2D.resize, tex2D.w, tex2D.h);
//add the instance to the list
Instances.Add(uuid, tex2D);
//return the instance, someone might want it (but they'll get it with the callback soon anyway)
return tex2D;
}
private void CleanupTexture(){
isLoaded = false;
//delete the gl texture
if(glTextureID != -1)
CleanupFastTexture2D(glTextureID);
glTextureID = -1;
//destroy the wrapper object
if(nativeTexture)
Destroy(nativeTexture);
//remove it from the list so further callbacks dont try to find it
if(Instances.ContainsKey(this.uuid))
Instances.Remove(this.uuid);
}
//to destroy a FastTexture2D object, you call Destroy() on it.
public void OnDestroy(){
CleanupTexture();
}
}
and you’ll need this code in a .mm (i use it in an ARC-enabled compiled .a plugin, so no [whatever release] is necessary. )
and you will need this dependency: https://github.com/coryalder/UIImage_Resize
extern "C" EAGLContext* ivcp_UnityGetContext();
typedef void (*TextureLoadedCallback)(int texID, int originalUUID, int w, int h);
static TextureLoadedCallback textureLoaded;
static GLKTextureLoader* asyncLoader = nil;
//(c) Brian Chasalow 2014 - brian@chasalow.com
void RegisterFastTexture2DCallbacks(void (*cb)(int texID, int originalUUID, int w, int h)){
textureLoaded = *cb;
}
void CreateFastTexture2DFromAssetPath(const char* assetPath, int uuid, bool resize, int resizeW, int resizeH){
@autoreleasepool {
NSDictionary* options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES],
GLKTextureLoaderOriginBottomLeft,
nil];
//maybe look here?
// http://stackoverflow.com/questions/16043204/handle-large-images-in-ios
NSString* assetPathString = [NSString stringWithCString: assetPath encoding:NSUTF8StringEncoding];
if(asyncLoader == nil)
asyncLoader = [[GLKTextureLoader alloc] initWithSharegroup:[ivcp_UnityGetContext() sharegroup]];
if(resize){
UIImage* img = [UIImage imageWithContentsOfFile:assetPathString];
__block UIImage* smallerImg = [img resizedImage:CGSizeMake(resizeW, resizeH) interpolationQuality:kCGInterpolationDefault ];
[asyncLoader textureWithCGImage:[smallerImg CGImage]
options:options
queue:NULL
completionHandler:^(GLKTextureInfo *textureInfo, NSError *outError) {
if(outError){
smallerImg = nil;
NSLog(@"got error creating texture at path: %@. error: %@ ", assetPathString,[outError localizedDescription] );
textureLoaded(-1, uuid, 0, 0);
}
else{
textureLoaded(textureInfo.name, uuid, resizeW, resizeH);
}
}];
}
else{
[asyncLoader textureWithContentsOfFile:assetPathString
options:options
queue:NULL
completionHandler:^(GLKTextureInfo *textureInfo, NSError *outError) {
if(outError){
NSLog(@"got error creating texture at path: %@. error: %@ ", assetPathString,[outError localizedDescription] );
NSLog(@"returning texID -1 ");
textureLoaded(-1, uuid, 0, 0);
}
else
{
//this will get returned on the main thread cuz the queue above is NULL
textureLoaded(textureInfo.name, uuid, textureInfo.width, textureInfo.height);
}
}];
}
}
}
void DeleteFastTexture2DAtTextureID(int texID){
@autoreleasepool {
GLuint texIDGL = (GLuint)texID;
if(texIDGL > 0){
if(glIsTexture(texIDGL)){
// NSLog(@"deleting a texture because it's a texture. %i", texIDGL);
glDeleteTextures(1, &texIDGL);
}
}
}
}
and you’ll need to inject ivcp_UnityGetContext() into the UnityAppController to get the surface.context, as in
extern "C" EAGLContext* ivcp_UnityGetContext()
{
return GetAppController().mainDisplay->surface.context;
}
or use any other means of getting the render context that you desire.
I hope you guys can integrate something along these lines into Unity directly.
Maybe one day I’ll make a plugin and release it on the asset store, but I’d rather you guys just fix it.
edit: fixed a bug that i inadvertently added as i cleaned up code to post it 
So if I’m following correctly, you mean: